Jet device for blowing yarn and process



Filed Sept. 13. 1956 All? EX/T R. F. DYER Feb. 16, 1960 JET DEVICE FORBLOWING YARN AND PROCESS 2 Sheets-Sheet 1 77754750 VAR/V RIC/MRO F DYERINVENTOR.

Feb. 16, 1960 R. F. DYER JET DEVICE FOR BLOWING YARN AND PROCESS 2Sheets-Sheet 2 Filed Sept. 13, 1956 I A/R/A/LET k '1- RICHARD E DYE/FINVENTOR. BY 42% 5.

ATTORNEYS JET DEVICE FOR BLOWING YARN AND PROCESS Richard F. Dyer,Kingsport, Tenn., assignor to Eastman Kodak Company, Rochester, N.Y., acorporation of New Jersey September 13, 1956, Serial No. 609,642

Application 16 Claims. (Cl. 28-1) This invention relates to devicesuseful for treating filamentarymaterials. More particularly, thisinvention concerns jet devices adapted for use in blowing air onto yarn.

This application is a continuation-in-part of my appli-f cation SerialNo. 400,544, filed December'ZS, 1953.

Inthetextile industry there are many instances where devices of theclass described are utilizable in the handling and the treating offilamentary material such as filaments, fibers, yarn, thread, tows andthe like. For example, in some instances such devices are useful inmotivating the material. In other instancesthe devices may be used toapply a certain type of treatment to the attenuated material. Or, in anumber of situations, combination of motivation and treatment maybedesired. 'The various purposes for which devices in accordance withthe present invention may be utilized will be further apparent from thedescription which follows. 4

'Forexample, in US. Patent 1,683,478 the general use of an air jet tomotivate filamentary material is described. In US. Patent 2,100,588 theuse of an air jet to impart a curl to yarn filaments is shown and in US.Patent 2,067,- 251 and air jet is provided to fluff up and loosen up abundle of filaments by placing them in a state of substantial butincomplete parallelism. The latter patent actually flufis up or bulksthe yarn enough so as to require a yarn takeup speed after the jet whichis less than the delivery speed to the jet, and the contraction in yarnlength results in an increase in denier. This patent shows the use ofthe jet to motivate the yarn material.

"One difiiculty with these existing jet devices and other of the priorart, however, was their inefficiency particularly as regards the largevolume of air at high pressures which was required to make such jetsoperative. in general, such jets were intended for processing heavytowsof yarn of say 20,000 denier with no particular attempt to use veryhigh velocity air.

It is, therefore, apparent that the development of small, highlyefiicient jet devices particularly adapted for the motivating andtreating of yarns in the range of 55 to 5000 denier represents a highlydesirable contribution to this art. For example, it has been found thatby applying high velocity air to yarn the cost of movingthe yarn can beappreciably reduced, and also that under certain conditions novel andunusual yarn effects can be produced.

After extended investigation I have discovered certain novel jet deviceswhich have utility for use in treating attenuated material, such asyarn, in various manners.

This invention has for one object to provide an improved device for usein motivating and/or treating filamentary material. Still another objectis to provide a jet device as aforementioned which is particularlyuseful for applying a stream or air or similar fluid to yarn or the likematerial. Still another object is to provide a device which is ofrelatively simple construction and which is susceptible of use invarious type of processes of treating filaments, fibers, yarn and thelike material. A particular object is to provide a jet device that isespecially adapted for use A 2,924,868 e e t dfeb- 1 60 in producingbulked. or lofted yarn. "Other objects will appear hereinafter. l I p aFor'an understanding of my invention,"ref erence will be made to theattached drawings forming a partof the presentapplication. In theattached drawings,

Fig. 1' is a sectional, side elevation view of one of the preferred jetdevices in aceo'rdancewith'the present invention. V, m2 J,- Figs. 2, 3and 4 are'likewise sectional, side cleyation views of other species ofjet devices.

Figs. 5 andv 6 are sectional views ofjajet generally corresponding tothe jet of, Fig.1,or parts thereof for showing the tilting oftheorificeplateas will be described hereinafter. I

Referring to Fig. 1, there'is shownin section the housing'oro'utsideshell 10 of a'jetdevicein accordance with the present invention.Thisdevice is made up of the several inner members 7, 8, 11 and 12 whichmaybe assembled together, for example by means of the threaded plugs 13land 36. A passageway ,14 extends through the jet device -so that thefilamentary material such as yarn maybe passed from a position at 15 toexit at position 16. This passageway or channel 14 in members 7, Sand 12is "of substantially uniform diameter except that at the lower portionthereof at 18 provision is made for causing some constriction of thepassageway to a conical shape.

Also, the outer surface of thelower portion of member 8 is suitablytapered as at 27, say to an angle between 50 to 90, for providinginconjunction with the tapered surface 26 of orifice plate '37 anannular orifice or passageway for metering the air flow into the lowercentral passageway 21. This orifice plate construction 37 isan importantfeature, of my device aswill be explained in more detail hereinafter.

Referring further to lowermember, 11, there is provided at 21 apassageway of substantially uniforr'n diameter, which passageway,however, flares outwardly a fewdegrees, as for example between 3 to 12in the portion 22.

The exact construction of this portion of my jet isof some importance inorder to assure a maximum velocity of air with a minimum air pressure inthe passageway of uniform diameter and a smooth transition, in theflared portion which exits to the atmosphere. For example, it has beenfound that highest efiiciency results when the length of the uniformpassage 21 is about V2 to 1 times its'diameter and the diameter of theflared portion 22 at the exit 16 end is about 2 times the diameter ofthe uniform passageway 21, and the taper off, the flare is between 6 and10 included angle. In'addition the inside diameter of the nozzle tip 30should be about of the diameter of the uniform passageway in member 11.These conditions result in a maximum intermingling of air and yarn inmember 11 and also when the members 11 and 12 are properly positionedcauses a suction in passageway 14 which makes the jet self-threading andparticularly suitable for removing and conveying yarn away from a godetor feed roll where no subsequent wind-up operation is involved. It wasalso noted'in using this jet design in the manner just described, i.e.to remove yarn from a roll, that the very high velocity of the aircaused an appreciable separation and subsequent tangling or loopiness inthe yarn when a large number of fibers made up the yarn strand. Theincrease in loopiness was much greater than had been obtained bypreviously known jet designs.

The upper portion of outside housing 10 is provided with a suitableinlet 23 such as a conduit, pipe, hose or the like for introducing thetreating fluid such as air. This opening leads into the chamber 24 whichchamber is of sufficient diameter to contain members 7 and 8 and toprovide a relatively uniform space thereabout. The exact size of chamber24 is not unduly critical. Preferably for the construction of this Fig.1 being described, the open parts or the like.

diameter (before inserting parts 'I and 8) would be about a half inch.However, the diameter may be changed say to inch or 1 inch. With largerdiameters deflectors could be inserted or a small amount of fillingmaterial such as Compressed wire or screening could beinserted ifdesired. However, the construction shown, gives good gas flow throughthe jet.

' It will be observed from the preceding description of my jet devicethat the internal construction thereof is such as to obtain a venturieffect on the, air flow. l have found that it is particularly'importantin the jet construction to be used in processing yarn and .the like,that there be reasonably exact concentri'city; That is, there'should beaccurate concentricity of the tip of the nozzle as at '30 and theopening of the orifice plate 31 andventuri throat as at 21. In otherwords, consideringthe device of Fig'. 1, passageway or channel 14preferably is exactlyaligned with the opening in the orifice plate andwith passageway 21, whichmeans that thespacing between surfaces 26 and27 would be relatively uniform around the entire circumference thereof.

The importance of accurately aligning the parts has been demonstrated bytest. Several jets were made up of substantially identical constructionexcepting that in a few of the jets the center line of certain of theparts, as parts 7 and 8, was off center a few hundreths of an inch. Suchjets did not produce as good bulked yarn as those jets where thealignment was within one-hundreths of an inch. However, when thealignment of these jets was corrected, they produced good yarn.

The other parts in Fig. l are gasket 34, spring washer 25 and bottomplug 36. It is thought, as may be readily noted from the drawing, thatit"can 'be seen these parts assist in permitting the tight assembly ofthe jet, yet so that it can readily be disassembied-for cleaning,replacement of By the construction just described I have found that astream of air may be effectively applied to filamentary material passingtherethroug'h. The air may be applied in varying amounts and undervarious pressures.

Reference is now made to Figs. 2 to 4 inclusive, showing various otherspecies of jet devices.

In these figures are shown jets in which the orifice plates 41, 42 and43 are positioned somewhat differently. These jets, excepting that ofFig. 2, are generally somewhat less efficient in operation than the jetsof Fig. l or 2. The

' amount of suction obtained is small and in some-cases these two formsmay not be self-threading. Insofar as imparting a loopy treatment to theyarn is concerned, they are about equal in performance to the jet ofFig. l but i require somewhat more airpressure to achieve the samedegree of loopiness.

Their chief advantage is simplicity of manufacture.

However, in Fig. 2, as in Fig. 1, is shown a form of the jet whichcombines an orifice and a venturi which results in greatly increasedefficiency and will impart improved loopiness to the yarn at lower airpressures than any of the'oth'er forms shown. The design proportions forthis jet 'fallin the sam'erange as those for the jet of Fig. 1.

It is preferred to use wear resistant ceramic materials for the entrancetube and venturi so that excellent resistance to yarn abrasion can beobtained. That is, the parts 8, 11 and 12 may be made of a' commerciallyobtainable material known as Alsimag. The various other parts such as 7,orifice plate 37, housing and the like may be made from metal such asbrass.

Fig. 4 is made up of the two parts, housing 51 and inlet tube 52 for theyarn, corresponding approximately to parts 10 and 7, 8 and 12 of Fig. 1.A suitable opening or other means is provided at 44 for-attaching aconduit pipe or otherwise providing for the introduction of the air orlike fluid. However, in this species of construction of Fig. 4 there isthe difference that there are provided two orifice plate members 43 and45. These plate membets are providedwith tapered orifices 46 and 47.

In these species of devices of Figs. 2 to 4, here again 'it will beobserved that there is concentricity of the tip or end of the nozzle andthe openings or opening of the orifice plates. As indicated above, it isdesirable that various parts are aligned so that the yarn or the likematerial being treated may travel in a reasonably straight, unobstructedpath through the jet.

The various species of jets shown in Figs. 2 to 4 may be used in someinstances for imparting special treatment to filamentary material. Or,in some ,instances where material of a diiferentsize (denier) thannormal or common filamentary material is being processed, these speciesof jets may be of value.

In all of my jet constructions when the jets are to be used for bulkingyarn, it is important that the jet give air flow that is smooth andstraight with little turbulence and no swirling of the air stream, inorder that proper bulking may takeplace. My jet constructions with, thevarious parts aligned asalrea'dy discussed in detail, permit suchuniform air now to be accomplished. On the otherhand, if asw'irling orcircular air flow does occur in the jet,'the centrifugal force of thisair flow may be such that it keeps the yarn pressed. against the wallsof the jet, thereby preventing the filaments from separating and formingloops. Consequently, improper jet construction and improper controlofthe air stream in the venturiof such jets may adversely effect-thequality and production rates of bulked yarn. 4

Mynovel jet constructions which contain an orifice plate therein, alsopossess further advantages. For example, it is possible in my jetstoslightlytilt the orifice plate. This may be accomplished by placing ashim under one side of the orifice plate or grinding a small sectionaway from. the shoulder of part 11, Fig. l. The amount of tilting of theorifice plate would be only a few hundrethsof an inch. Such tiltingpermits the production of bulk yarn with smaller loopsthan when theorifice plate is not tilted. 'Also, a slight tilting may assist inincreasing 72. Since the jet shown in Fig. 5 otherwise is substantiallysimilar to the jet of Fig. 1, further description of the other partsdoes not appear to be required.

The accomplishment of the tilting of the orifice plate as discussedabove, may be further understood referring to Fig.- 6. In this Fig. 6there is shown a part 71substantially corresponding to part 11 ofFig. 1.As indicated at 73, the shoulder 74 maybe ground off a slight amount,for example ',0022-.028 inch in order that the orifice plateaforementioned will be tilted slightly when the jet is assembled, p q

The jets of the present invention possess a number of other advantagesas compared with prior art jets. The

ets of the, present invention generally permit-the use of lowerairpressurefthan jets heretofore used for the same purpose. The action ofthe jets of the present invention is much gentler on the yarn thanpriorart jets- The small jets Ofthe present invention will accommodate mostany size yarn from 75 denier to 900 denier withouthaving to make changesinthe jet parts. The large jets will handle from 900-7000 denier withoutchangingparts.

The jet devices described above may be used. to process yarn,particularly to convert multi-filament continuous yarn into bulked yarn.In order to operate. the jet of Fig. 1, the air supply to opening 23could be of the order of 5-50 lbs. p.s.i. Under such conditions the yarncoming off a Godet'roll would be motivated through the jet device at atension of about .05 gram/denier for the purpose of keeping waste yarnfrom accumulating on the rolls during a dofling of bolbbins or a yarnbreak at the windup means. p

Theyarn emergin g from the jet positioned adjacent the Cu. Ft. Jet AirPer Hr.

Exhaust Jet. Air,

Air, c.f.m. c.f.m.

Intake Air,

c.f.m.

Tension, Gram/ Jet Air p.s.i. ga e g Denier In considering the abovetable, it will be kept in mind that lower .or higher pressures thanthose illustrated in the table may be used, and the particular pressureused is controlled, to some extent, by the type jet being employed. Forexample, referring to the jet construction of Fig. 2, pressures between3 and lbs. p.s.i. are utilizable with good results.

Referring to the jet of Fig. 3, for example, the use of air pressure ofthe order of 7 to 9 lbs. produced good uniform loopiness in yarn passingtherethrough.

In all of the jets described, it is possible to equip the orifices (ormake the entire part) where the filamentary material may come in contactwith the parts with suitable wear resistant surfaces. Ceramic materialscontaining titanium oxides, aluminum oxides and silica have been foundto be quite satisfactory.

'The filamentary material resulting from the treatment of continuousmulti-filament yarn in the several jets which have been described above,gives a product which may be used for substantially all the purposes forwhich comparable untreated continuous yarn has heretofore been used.That is, the treatment of the yarn in the jets of the present inventionrenders the yarn more bulky and softer but there are still obtainedcontinuous filaments which may be woven into fabrics or otherwise usedthe same as yarn that has not been processed in the jet of the presentinvention. For example, a 300 denier cellulose acetate yarn having 75filaments, when processed in the jet in accordance with Fig. 1, wasconverted into a prod net of the following characteristics:

Example 1 Input Yarn Output Yarn 360 Denier.

75 Filaments.

80 Ou.Ins./Lb. S.V.

Loopy, Worsted-like Appearance.

300 Denier.

75 Filaments.

32 Cu.Ins./Lb. Specific Volume. Smooth Lustrous Appearance.

After twisting the foregoing yarns they were woven into a crowfoot satinas filling yarn. The warp was composed of 108 ends of 150 denier 38filament .9 t.p.i. twist yarn.

The fabric had the following characteristics:

Input Yarn Fabric Output Yarn Fabric 300/75/22 Bright Luster. ssons/szBright Luster. 40 Picks/Inch. 36 Picks/Inch.

. 3.70 ozs./sq. yard fabric weight. 3.94 ozs./Sq. Yd.

.010 Fabric Thickness. .014 Fabric Thickness.

36.7 F. Temperature Rise. 30.7 F. Temperature Rise.

(High temperature rise indicates poor insulation properties.)

Fabric had smooth silky hand. Fabric had lofty, light, and

. worsted-like hand.

The jet used for processing this yarn had the following. T- dimensions:1

Diameter of inlet to nozzle 12 .125".

Diameter of outlet of nozzle 8 .047". f

Diameter of orifice hole 31 .094".

Included angle of nozzle 8 60'.

Included angle of orifice 37 Entrance angle of venturi 11 35' Venturithroat diameter .106".

Venturi throat length .062".

Venturi exit angle 10? Air pressure used 8 p.s.i. gage.

Air usage 2.5 to 3.0 cfm. standard air.

Example 2 illustrates the processing of a heavy denier cellulose acetateyarn in a jet as shown in Fig. 1, but modified to handle large yarns. 1

Input Yarn Output Yarn 1800 Denier. 2200 Denier. Filaments. 110Filaments.

.75 Twist t.p.i. 2. Smooth lustrous yarn.

.75 Twist t.pLi. Z. Loopy wool-like yarn.

The foregoing output ortreated yarn was 3 plied with 1% turns/inch Stwist and tufted into a looppile rug to which the yarn imparted a highdegree of cover,.resilience,and good wool-like appearance which couldnot beobtained with theuntreated input yarn. The jet used, forprocessing this yarn had the, following dimensions: 7

Diameter of inlet to nozzle 12 .156". 1 Diameter of nozzle outlet 8.145". Included angle of nozzle 8 60". Diameter of orifice hole 31.177". Entrance angle of venturi 11 60. Included angle of orifice 37 90.Venturi throat diameter 11 .189." Venturi throat length 11 .150";Venturi exit angle 11 10.

Air pressure used 20 p.s.i. gage. Air usage 10 cfm. standard air.

However, the jet devices of the present invention-may also be used inthe removal of waste yarn from Godet to feed rolls. The yarn removedby-means of the jets herein describedis by reason of its bulky separatedfilament state more readily redissolved and thus improves the recoveryof waste yarn and its processing for respinning. Therefore, the exactmanner of utilizing the jets herein described is not a limitation on thepresent invention.

While in the above description, reference has been made to treating ofcellulose acetate yarn, in a similar manner other yarns such ascellulose acetate butyrate, cellulose acetate propionate, polyester,acrylic and the like yarns may be processed in a-comparable manner. Thedenier of the yarn is usually between -450. However, heavy denier, say3000 to 8000 may also be processed. The number of filaments arepreferably above30.

- I claim:

l. A jet device adapted for use in the textile industry, comprising anelongated outer member which includes a head portion and a tail portion,said member being provided with an air chamber in'the member, said airchamber communicating with a relatively thin ceramic orifice platepositioned between the head and tail portions, said plate merging into aflared venturi-type passageway, a tube member having a substantiallyuniform passageway therethrough positioned in the air chamber so thatsaid passageway discharges into said orifice-plate, the apparatusassembly. being characterized in tbat the passageway and the orificemember are in relatively accurate concentricity. r

2. A jet device adapted for use in the textile industry, comprising anouter member which'has head and tail sections; said member beingprovided with'an air chamber in thehead section, said air chambercommunicating with an orifice plate positioned about mid-way of themember, said orifice plate connecting with a venturi member, anelongated tube member provided with a substantially uniform passagewaytherethrough positioned in the air chamber, which-passageway ispositioned to discharge into the centerof said orifice plate, theapparatus assembly beingcharacterized in that allof the passagewaysthrough the jet "are-in accurate concentricity.

'3. A jet device particularly adapted for treating continuousmulti-filament yarn to convert the yarn to bulked yarn, whichcomprises ajet housing which housing is provided with an inlet adapted for theintroduction of arr into an air chamber within the interior of saidhousing, a

tube member-"provided" with a-passageway-of substan tially uniformdiameter positioned in one end of said housing'and'leading through saidair chamber, a wider passageway on the other end of said housing and arelatively thin slightly tilted orifice plate within the housingpositioned so that the first-mentioned passageway and the air chamberdischarge through said orifice plate into the last-mentioned passageway.

4. A'jet device particularly useful for treating continuousmulti-filament yarn, comprising an elongated jet 1 housing having aninlet on the side thereof adapted for the introduction of air into anair chamber within the interior of said housing, a tube memberpositioned in one end of'said housing, said tube'member being providedwith a substantially uniform passageway therethrough, which passagewayand tube member terminate in a conical tip, said tube member beingcomprised of a plurality of parts removably positioned in the end ofsaid housing, a venturi-type tube member having a flared exit portionremovably positioned by means of a threaded plug in the other end ofsaid housing, and an orifice plate having a tapered orifice thereinpositioned between the two tube members, said tube members and orificeplate being aligned so that yarn entering one end of the device may passin a substantially straight line tluough the device and out of the otherend thereof.

5. A jet device as in claim 4 but in which the orifice plateis tiltednot more than a few hundredths of an inch. 6, 'A jet device particularlyadapted for treating con- I tinuous multi-filament yarn for convertingthe yarninto bulk yarn comprising a jet housing provided with an inletmeans on the side of the housing for introducing air into an air chamberof about V2," diameter within the interior of the housing, an externallyrelatively smooth tube member provided with a substantiallyuniforrnpassageway of less than A" diameter extending through said air chamber,said tube closing up one end of said air chamber, an orifice platepositioned on the other end of said air chamber and aligned with'saidtube so that said tube can discharge substantially concentricallythrough the opening in said orifice plate and the other end of saidhousing being provided with a removably positioned venturi-type of tube.

7. A jet device adapted for use in the textile industry, comprising anelongated outer housing, including a head portion and a:.tail portion,said housing being provided with an air chamber in the head thereof,said air chamber communicating with a relatively thin orifice platepositioned about mid-way of the housing, said orifice plate being atleast approximately centered in the housing, another member providedwith a substantially uniform pasageway therethrough positioned in theair chamber,

rate axial alignment.

tion-and a diverging exit portion of less than '30 in cluded'anglelocated below said orifice plate,-the apparatus assembly beingcharacterized in that the passageway, orifice plate, and venturi memberare in relatively accuthereof, the air"chamber communicating with arelatively thin orifice plate positioned generally adjacent the exit endof the air chamber, the aforementioned tail member being positionedgenerally adjacent the orificeplate on the opposite side thereof fromthe air chamber, this venturi tail member being characterized in that itis composed of a converging section, a short parallel tube-like sectionand a diverging section. v

9. A jet device for bulking yarn comprising a housing separated into anupper and lower section by sagas. inlet pipe leading to the side of thehousing, a gas chamber within said housing, a tube which terminates in aconical 'tip leading through said gas chamber,'and at least one thinplate orifice positioned belowsaid tipand a venturi nozzle positionedbelow said thin plate orifice, the apparatus being characterized in thatsaid tip and said or'ificeare positioned in.v relatively accurateconcentricity.

a 10; A jet device adapted for use in the textile industry, comprisingan outer member which has head and tail sections, said member beingprovided with an air chamber in the head section provided with an inletfor the introduction of a gaseous media into said chamber within thehead section, said 'airchamber communicating with an orifice platepositioned about mid-way of the member, said orifice plate connectingwith a venturi member, an elongated tube member provided with asubstantially uniform passageway therethrough positioned in the airchamber, which passageway is positioned to discharge into the center ofsaid orifice plate, the apparatus assembly being characterized in thatall of the passageways through the jet are in accurate concentricity.

11. An apparatus for treating a plurality of strands ofcontinuousmulti-filamcnt yarn which apparatus is adapted to convert static airpressure into velocity pressure with a minimum of air turbulence and amaximum of streamlined flow, said apparatus comprising a body memberhaving upper and lower portions, a tube terminating in a nozzle threadedinto the upper portion of said body member and extending into the bodymember, an orifice plate having a centrally positionedorifice locatedwithin said body member so that said orifice is aligned with saidnozzle, a venturi tube abutting said orifice and threaded into the lowerportion of said body member,

said venturi tube having an entrance throat and a straight continuousmulti-filament yarn which apparatus is adapted said other member beingpositioned to discharge at least approximately into the center of saidorifice plate, a venturi member composed of a converging portion of lessthan 135"includedang1e,.a short cylindrical throat perto convert staticair pressure .into velocity pressure with a minimum of air turbulenceand a maximum of streamlined flow, said apparatus comprising a hollowbody member having upper and lower portions, a tube terminating in anozzle securely afiixed to the upper portion of said body member andextending into the body member, an orifice plate having a centrallypositioned orifice located within said body member so that said orificeis aligned with and is closely associated with'said nozzle, a venturitube abutting said orifice and securely fastened vto the lower portionof said body member, said venturi tube having an entrance throatslightly largerthan said orifice,

9 V and a straight portion approximately equal to the diam eter of saidorifice, an exit throat in the lower portion of said venturi, said exitthroat having a taper whereby air fiow is at very high velocity throughthe orifice, loses velocity in the entrance throat but regains velocityin the straight portion and thereafter expands evenly and loses velocityin the exit taper.

13. A process for treating continuous multi-filament yarn, whichcomprises introducing said yarn into a jet containing a nozzle, plateorifice and venturi and into the center of a column of high velocitystreamline air flow in association therewith, impinging said air flow ata low angle of incidence onto said yarn in such a manner that the yarnis maintained substantially in the center of said streamline air flow,while at the same time being thoroughly admixed with the air, insequence decelerating and then accelerating said streamline air flow toa high velocity and then evenly decelerating said streamline air flowsuch that the yarn is caused to expand radially, then contract andreform into yarn while being maintained in the central portion of theair stream and abruptly removing said treated yarn from the streamlineair How in a radial direction.

14. A process in accordance with claim 13 wherein the streamline flowwhich while exerting forces in axial and radial directions on the yarndoes not exert any torque forces which would cause the yarn to twist orturn to any substantial extent.

15. The process in accordance with claim 13 wherein the streamline flowis free of any centrifugal motions of the air flow which might tend topush the yarn filaments against the walls of the venturi.

16. A process in accordance with claim 13 wherein the orifice plate isaligned with and is closely associated with said nozzle so that the rateof air flow is substantially equal at each point around the annularopening formed by the nozzle and the plate orifice.

References Cited in the file of this patent .UNITED STATES PATENTSv2,622,961 Finlayson et al. Dec. 23, 1932 2,667,964 Miller Feb. 2, 19542,670,154 Sutherland Feb. 23, 1954 2,783,609 'Breen Mar. 5, 1957

